Conventionally, the safe driving support technology is put in practical use in which a vehicle-to-vehicle (V2V) communication system and a road-to-infrastructure (V2I) communication system are used.
For example, an on-vehicle device mounted on a vehicle sends (hereinafter, “transmits” is used) a radio signal vehicle information indicating a position, a running speed, and the like of a self-vehicle, obtained by using the global navigation satellite system (GNSS) and various sensors; and the on-vehicle device receives vehicle information similarly transmitted from another vehicle in the periphery. Further, such an on-vehicle device receives road information indicating a condition of a pedestrian at an intersection, traffic condition, or the like transmitted from a roadside device when passing by near the roadside device. Note that the above-described vehicle information is received not only by the on-vehicle device in another vehicle but also by a near-by roadside device.
Peripheral environment of each vehicle changes from time to time. Further, there is much information that needs to be immediately transferred, such as occurrence of a traffic accident. Therefore, an on-vehicle device compatible with the vehicle-to-vehicle communication system and the vehicle-to-infrastructure communication system (hereinafter, the device is referred to as “wireless system device”) is typically configured to autonomously and cyclically (for example, at a cycle of 100 ms) transmit vehicle information.
The above-described exchange of information makes it possible to anticipate potential danger and accident in real time and with a high degree of accuracy; therefore, it is possible to accurately provide information, alert, and the like for preventing danger and accident to drivers and pedestrians.
Along with export of vehicles to foreign countries, cases are increasing in which a wireless system device mounted on a vehicle is brought out to foreign countries. However, in this case, there will be a problem of radio wave interference with other wireless communication systems. That is because wireless communication systems and frequency bands used for safe driving assistance are not standardized worldwide, there are many systems in the world, and in addition, new systems are under consideration for use. For example, while the V2V communication system and the V2I communication system using the 760 MHz band are in practical use in Japan, a system using the 5.9 GHz band is scheduled to be in practical use in North America and Europe.
To address the problem mentioned above, for example, one can avoid the radio wave interference when a vehicle is exported, by employing the technique described in PTL 1 (hereinafter, referred to as “conventional art”). In the conventional art, by using positional information indicating a controlled area in which sending of a radio signal is inhibited, it is determined whether a current position is entering the controlled area, and when it is determined that the current position is entering the controlled area, sending of a radio signal is limited or stopped.